His practice focuses on banking and finance, in particular in the fields of private banking and private clients. He advises banks and financial institutions on regulatory and clients' (structuring and financing) matters. He also advises private clients on all aspects of trusts and international estate planning. Grégoire has extensive experience in corporate and transactional matters, with a focus on the shipping and business aviation industries.

Grégoire studied at the University of Geneva and obtained his law degree in 2004. After earning a Master of Advanced Studies (LL.M.) in business law from the University of Geneva in 2006, he worked as corporate tax consultant at a major auditing firm in Geneva. In 2007, he received a certificate in international business and finance from New York University. Grégoire was admitted to the Swiss bar in 2009 (ranked 2nd) and joined Schellenberg Wittmer as an associate in 2010. In 2013 and 2014, Gregoire was seconded to the trust company of a major Swiss private bank in Singapore.